Historic St. Mary's Mission is at the w. end of Fourth St. at 315 Charlos St. The mission was established in 1841 by Father Pierre DeSmet. The present complex includes the 1880s-style restored chapel and a study, dining room and kitchen. Also restored is Father Anthony Ravalli's log house, which contains a pharmacy with a “ride-up” window. Chief Victor's cabin is a small museum that displays original furnishings and Native American and missionary artifacts.
Guided tours are available. Picnicking is permitted.